Golf ball with specified ratio of ball spin rate to launch angle

ABSTRACT

A golf ball that, when hit with an iron, has a higher spin rate and launch angle than existing golf balls currently available on the market is disclosed. The same golf ball may have a compatible driver spin rate and launch angle against existing golf balls currently available on the market. When the golf ball is hit with a driver, the golf ball may have a spin rate to launch angle ratio ranging from about 190 to about 360. When the golf ball is hit with an iron other than a pitching wedge, the golf ball may have a spin rate to launch angle ratio ranging from about 500 to about 600.

This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/512,973, entitled “Golf Ball With Specified Ratio Of Ball Spin Rate To Launch Angle”, and filed on Jul. 29, 2011, which application is hereby incorporated by reference.

BACKGROUND

The present invention relates generally to a golf ball having different play characteristics in different situations.

The game of golf is an increasingly popular sport at both amateur and professional levels. A wide range of technologies related to the manufacture and design of golf balls are known in the art. Such technologies have resulted in golf balls with a variety of play characteristics. For example, some golf balls have a greater spin rate and/or launch angle than other golf balls. To have more control over a golf ball in iron shots, especially when the golf ball flies against the wind, it is desirable for the launch angle of the ball to be low and the spin rate of the ball to be high. However, such a high spin rate may not be desirable for driver shots because driver shots may drop too soon in flight, causing the golf ball to fly a shorter distance. Thus, it would be advantageous to be able to make a golf ball that has a different spin rate associated with different types of clubs.

SUMMARY

A golf ball that, when hit with an iron, has a higher spin rate and launch angle than existing golf balls currently available on the market is disclosed. The same golf ball has a compatible driver spin rate and launch angle against existing golf balls currently available on the market.

In one aspect, the disclosure provides a golf ball that may have an inner core layer, an outer core layer enclosing the inner core layer, an inner cover layer enclosing the outer core layer, and an outer cover layer enclosing the inner cover layer. The inner core layer may have a higher coefficient of restitution than the outer core layer, the inner cover layer, and the outer cover layer. When the golf ball is hit with a driver having a loft angle of less than 15 degrees, the golf ball may have a spin rate to launch angle ratio ranging from about 190 to about 360. When the golf ball is hit with an iron having a loft angle of less than 40 degrees, the golf ball may have a spin rate to launch angle ratio ranging from about 500 to about 600. Performing the BS/LA 160 mph driver test on the golf ball may result in the golf ball having a spin rate to launch angle ratio ranging from about 190 to about 230. Performing the BS/LA No. 4 iron test on the golf ball may result in the golf ball having a spin rate to launch angle ratio ranging from about 510 to about 580. Performing the BS/LA No. 6 iron test may result in the golf ball having a spin rate to launch angle ratio ranging from about 510 to about 580. Performing the BS/LA high loft angle test on the golf ball may result in the golf ball having a spin rate to launch angle ratio ranging from about 440 to about 480. The inner core layer may include at least one highly neutralized acid polymer composition. The inner core layer may have a coefficient of restitution value ranging from about 0.795 to about 0.88. The inner core layer may have a coefficient of restitution value that is about 0.005 to about 0.02 greater than the coefficient of restitution value of the golf ball. The inner cover layer may have a Shore D hardness ranging from about 60 to about 80.

In one aspect, the disclosure provides a golf ball that may have an inner core layer, an outer core layer enclosing the inner core layer, an inner cover layer enclosing the outer core layer, and an outer cover layer enclosing the inner cover layer. The inner cover layer may have a greater specific gravity than the thermoset outer core layer. When the golf ball is hit with an iron having a loft angle of less than 40 degrees, the golf ball may have a first spin rate to launch angle ratio. When the golf ball is hit when with a driver having a loft angle of less than 15 degrees, the golf ball may have a second spin rate to launch angle ratio that is at least 240 lower than the first spin rate to launch angle ratio. The golf ball may have a second spin rate to launch angle ratio that is at least 310 lower than the first spin rate to launch angle ratio. The inner cover layer and outer cover layer may both comprise thermoplastic materials. The outer core layer may include a polybutadiene rubber. The thickness of the outer core layer may range from about 0.5 to about 2 mm. The inner core layer may have a coefficient of restitution value that is about 0.005 to about 0.02 greater than the coefficient of restitution value of the golf ball. The inner cover layer may have a Shore D hardness ranging from about 60 to about 80.

In one aspect, the disclosure provides a golf ball that may have an inner core layer, an outer core layer enclosing the inner core layer, an inner cover layer enclosing the outer core layer, and an outer cover layer enclosing the inner cover layer. The inner core layer may have a higher coefficient of restitution than the outer core layer, the inner cover layer, and the outer cover layer. When the golf ball is hit with a driver having a loft angle of less than 15 degrees, the golf ball may have a spin rate ranging from about 2400 rpm to about 2800 rpm. When the golf ball is hit with a first iron having a loft angle of less than 40 degrees, the golf ball has a spin rate ranging from about 6800 rpm to about 7300 rpm. The first iron having a loft angle of less than 40 degrees may be a No. 6 iron. When the golf ball is hit with the first iron having a loft angle of less than 40 degrees, the golf ball may have a launch angle ranging from about 12 degrees to about 13.5 degrees. When the golf ball is hit with a second iron having a loft angle of less than 40 degrees, the golf ball may have a spin rate ranging from about 5300 rpm to about 5600 rpm. When the golf ball is hit with the second iron having a loft angle of less than 40 degrees, the golf ball may have a launch angle ranging from about 9.5 degrees to about 10.5 degrees. The second iron having a loft angle of less than 40 degrees may be a No. 4 iron. When the golf ball is hit with a second iron having a loft angle of 40 degrees or greater, the golf ball may have a spin rate ranging from about 10,500 rpm to about 11,100 rpm. When the golf ball is hit with a second iron having a loft angle of 40 degrees or greater, the golf ball may have a launch angle ranging from about 21 degrees to about 23 degrees.

Other systems, methods, features and advantages of the invention will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the invention, and be protected by the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.

FIG. 1 illustrates the trajectory of a golf ball prepared according to the present disclosure compared with the trajectory of a different type of golf ball after being hit by a driver;

FIG. 2 illustrates the trajectory of a golf ball prepared according to the present disclosure after being hit by a pitching wedge; an

FIG. 3 is a golf ball according to the exemplary embodiment of FIGS. 1 and 2.

DETAILED DESCRIPTION

Generally, the present disclosure relates to a golf ball having a variable spin rate (backspin) and launch angle associated with striking the golf ball with different types of golf clubs. The structure of the disclosed golf ball may cause the golf ball to experience a high spin rate when the golf ball is hit with an iron. However, the same golf ball may experience a lower spin rate when the golf ball is hit with a driver. As a result, the disclosed golf ball may have different trajectories associated with different types of golf clubs.

FIGS. 1-3 show an exemplary embodiment of a golf ball 100. In FIG. 1, a golfer 142 has used a driver 144 to hit golf ball 100 and another type of golf ball, golf ball 182, off of a tee 146 located in a tee box 148. FIG. 1 demonstrates a comparison between a trajectory 150 of golf ball 100 and a trajectory 180 of golf ball 182 after each of the golf balls have been struck by driver 144. Each of the golf balls has a different trajectory profile because each of the golf balls has a different spin rate associated with being hit by driver 144. Trajectory 150 is more parabolic than trajectory 180 because golf ball 100 has a lower spin rate than golf ball 182 after being struck by driver 144. The higher spin rate of golf ball 182 may cause golf ball 182 to have more lift as the golf ball continues flying through the air. As a result, the slope of trajectory 180 may increase throughout the flight of golf ball 182 before beginning to descend back to the ground, as shown in FIG. 1. Due to the increase in slope of trajectory 180, golf ball 182 may not fly as far as golf ball 100. Typically, the objective of using a driver is to send a golf ball a long distance. Thus, the distance gained by the lower spin rate of golf ball 100 may be desirable for driving a golf ball.

FIG. 2 shows a second trajectory 160 of golf ball 100 after being hit by a pitching wedge 154 out of a bunker 158 onto a green 162. Trajectory 160 of golf ball 100 in FIG. 2 is more similar to trajectory 180 of golf ball 182 in FIG. 1 because golf ball 100 has a higher spin rate in FIG. 2 than in FIG. 1. This higher spin rate may cause golf ball 100 to have more lift as golf ball 100 continues flying through the air. As a result, the slope of trajectory 160 may increase throughout the flight of golf ball 100 before beginning to descend back to the ground, as shown in FIG. 2. In addition to adding more lift to the flight of golf ball 100, a higher spin rate may cause golf ball 100 to land softer and to roll less upon landing. Accordingly, a higher spin rate may allow a golfer to have more control of a golf ball. Typically, the objective of using a pitching wedge is to send a golf ball a short distance with considerable precision. Thus, the control gained by the lower spin rate of golf ball 100 may be desirable for pitching a golf ball near a green.

In addition to having different spin rates associated with different clubs, golf ball 100 may have different launch angles associated with different clubs. An angle α is the launch angle of golf ball 100 in FIG. 1 and an angle β is the launch angle of golf ball 100 in FIG. 2. In the exemplary embodiment, angle α is about 12 degrees and angle β is about 24 degrees.

Tables 2-6 show the results of tests performed on test balls, which include golf balls prepared according to the present disclosure and existing golf balls currently available on the market. The golf balls prepared according to the present disclosure include Examples 1-5. The existing golf balls currently available on the market include Comparative Examples 1-8, details of which are shown in Table 1 (where PBR is polybutadiene rubber). The results shown in Tables 2-6 include initial velocity (IV), launch angle (LA), backspin (BS), and BS/LA ratio. All results for IV have an uncertainty of ±1 mph. All test results for LA have an uncertainty of ±1 degree. The tests yielding the results in Tables 2-6 are described in more detail below.

TABLE 1 Comparative Test Balls Ball Name and Brand Ball Pieces Core Cover Tour B330-S by Comparative Four (4) PBR Urethane Bridgestone Sports Example 1 Dot Tour by Nike Golf Comparative Three (3) PBR Urethane Example 2 Penta TP by Comparative Five (5) PBR Urethane Taylormade Example 3 ProV1 by Titleist Comparative Three (3) PBR Urethane Example 4 ProV1x by Titleist Comparative Three (3) PBR Urethane Example 5 Tour D by Nike Golf Comparative Three (3) PBR Urethane Example 6 Tour i(s) by Callaway Comparative Four (4) PBR Urethane Example 7 Tour by Nike Golf Comparative Three (3) PBR Urethane Example 8 Z-Star by Srixon Comparative Three (3) PBR Urethane Example 9

Table 2 shows the results of a BS/LA 160 mph driver test. The BS/LA 160 mph driver test involves hitting the test balls with a driver having a head speed of about 120 mph±1 mph. The driver used in the test is a Nike Victory Red Pro driver having an X-Flex (extra stiff) shaft, a 58-degree lie angle, and a 9.5-degree loft angle. The calibration ball for the BS/LA 160 mph driver test is a USGA/R&A Calibration model golf ball commercially available by Bridgestone Sports. To calibrate the BS/LA 160 mph driver test, the conditions are set to cause the calibration ball to have an initial velocity of 159.5 mph±1 mph, a launch angle of 12.9 degrees±1 degree, and a backspin of 2200 rpm±150 rpm when the calibration ball is hit with the driver having a head speed of about 120 mph±1 mph.

The results of the BS/LA 160 mph driver test show that the BS/LA ratio of golf balls prepared according to the present disclosure are comparable to the BS/LA ratio of the existing golf balls currently available on the market. For example, Comparative Example 2 has a BS/LA ratio of 198.9844. Similar to these results, Example 3 has a BS/LA ratio of 199.2000. The ranges of BS/LA ratios of the test balls and the existing golf balls currently available on the market overlap. The BS/LA ratios of the existing golf balls currently available on the market fall within a range of about 166 to about 199. The BS/LA ratios of the test balls in Table 2 fall within a range of about 199 to about 219. In some embodiments, the BS/LA ratios resulting from performing the BS/LA 160 mph driver test on a golf ball prepared according to the present disclosure may range from about 195 to about 220. In some embodiments, the BS/LA ratios resulting from performing the BS/LA 160 mph driver test on a golf ball prepared according to the present disclosure may range from about 190 to about 230.

TABLE 2 BS/LA 160 MPH DRIVER TEST Initial Launch Velocity Angle Backspin (IV) (LA) (BS) Ball (mph) (Degrees) (rpm) BS/LA Example 1 161.8 12.5 2671 213.6800 Example 2 161.8 12.4 2712 218.7097 Example 3 161.6 12.5 2490 199.2000 Example 4 162.0 12.5 2536 202.8800 Example 5 161.9 12.6 2524 200.3175 Comparative 160.5 13.0 2325 178.8462 Example 1 Comparative 161.1 12.8 2547 198.9844 Example 2 Comparative 160.6 13.0 2282 175.5385 Example 3 Comparative 161.5 12.9 2341 181.4729 Example 4 Comparative 161.7 13.0 2158 166.0000 Example 5 Comparative 160.9 13.0 2208 169.8462 Example 6 Comparative 160.9 13.1 2329 177.7863 Example 7 Comparative 161.0 12.8 2462 192.3438 Example 8 Calibration 159.5 12.9 2200 170.5426 Ball Comparative 160.5 12.9 2337 181.1628 Example 9

Table 3 shows the results of a BS/LA 139 mph driver test. The BS/LA 139 mph driver test involves hitting the test balls with a driver having a head speed of about 102 mph±1 mph. The driver used in this test is a Nike Dymo₂ driver having an S-Flex (stiff) shaft, a 62-degree lie angle, and a 10.5-degree loft angle. The calibration ball for the BS/LA 139 mph driver test is a USGA/R&A Calibration model golf ball commercially available by Bridgestone Sports. To calibrate the BS/LA 139 mph driver test, the conditions are set to cause the calibration ball to have an initial velocity of 137 mph±1 mph, a launch angle of 12.1 degrees±1 degree, and a backspin of 3289 rpm±150 rpm when the calibration ball is hit with the driver having a head speed of about 102 mph±1 mph.

The results of the BS/LA 139 mph driver test show that the BS/LA ratio of golf balls prepared according to the present disclosure are comparable to the BS/LA ratio of the existing golf balls currently available on the market. For example, Comparative Example 2 has a BS/LA ratio of 314.2857. Similar to these results, Example 4 has a BS/LA ratio of 328.2051. The ranges of BS/LA ratios of the test balls are substantially similar to the BS/LA ranges of the existing golf balls currently available on the market. The BS/LA ratios of the existing golf balls currently available on the market fall within a range of about 268 to about 315. The BS/LA ratios of the test balls in Table 3 fall within a range of about of about 328 to about 350. In some embodiments, the BS/LA ratios resulting from performing the BS/LA 139 mph driver test on a golf ball prepared according to the present disclosure may range from about 320 to about 360. In some embodiments, the BS/LA ratios resulting from performing the BS/LA 139 mph driver test on a golf ball prepared according to the present disclosure may range from about 315 to about 380.

TABLE 3 BS/LA 139 MPH DRIVER TEST Initial Launch Velocity Angle Backspin (IV) (LA) (BS) Ball (mph) (Degrees) (rpm) BS/LA Example 1 138.4 11.6 4011 345.7759 Example 2 138.1 11.6 4056 349.6552 Example 3 138.2 11.6 3954 340.8621 Example 4 138.3 11.7 3840 328.2051 Example 5 138.1 11.7 3852 329.2308 Comparative 137.2 12.1 3471 286.8595 Example 1 Comparative 137.8 11.9 3740 314.2857 Example 2 Comparative 137.5 12.1 3402 281.1570 Example 3 Comparative 137.9 12.2 3469 284.3443 Example 4 Comparative 137.9 12.2 3361 275.4918 Example 5 Comparative 137.8 12.3 3298 268.1301 Example 6 Comparative 138.0 12.1 3503 289.5041 Example 7 Comparative 137.5 11.9 3692 310.2521 Example 8 Calibration 137.0 12.1 3289 271.8182 Ball Comparative 137.4 12.2 3459 283.5245 Example 9

Table 4 shows the results of a BS/LA No. 4 iron test. The BS/LA No. 4 iron test involves hitting the test balls with a No. 4 iron having a head speed of about 102 mph±1 mph. The No. 4 iron used in this test is a Nike Victory Red Split Cavity No. 4 iron having an X100 (extra stiff) shaft, a 60-degree lie angle, and a 24-degree loft angle. The calibration ball for the BS/LA No. 4 iron test is a USGA/R&A Calibration model golf ball commercially available by Bridgestone Sports. To calibrate the BS/LA No. 4 iron test, the conditions are set to cause the calibration ball to have an initial velocity of 137.3 mph±1 mph, a launch angle of 10.9 degrees±1 degree, and a backspin of 4186 rpm±150 rpm when the calibration ball is hit with the No. 4 iron having a head speed of about 102 mph±1 mph.

The results of the BS/LA No. 4 iron test show that the BS/LA ratio of golf balls prepared according to the present disclosure are substantially different from the BS/LA ratio of the existing golf balls currently available on the market. For example, at 467.9808, Comparative Example 2 has the highest BS/LA ratio of the existing golf balls currently available on the market. At 519.8039, Example 5 has the lowest BS/LA ratio of the golf balls prepared according to the present disclosure. The difference between the BS/LA ratio of the Comparative Example 2 and the BS/LA ratio of the Example 5 is 51.3281. The BS/LA ratios of the existing golf balls currently available on the market are substantially different from the BS/LA ratios of the golf balls prepared according to the present invention. The BS/LA ratios of the existing golf balls currently available on the market in Table 4 fall within a range of about 358 to about 468. Generally, the BS/LA ratios of the golf balls prepared according to the present disclosure in Table 4 fall within a range of about 519 to about 547. In some embodiments, the BS/LA ratios resulting from performing the BS/LA No. 4 iron test on the golf balls prepared according to the present disclosure range from about 500 to about 600. In some embodiments, the BS/LA ratios resulting from performing the BS/LA No. 4 iron test on the golf balls prepared according to the present disclosure range from about 510 to about 580.

TABLE 4 BS/LA NO. 4 IRON TEST Initial Launch Velocity Angle Backspin (IV) (LA) (BS) Ball (mph) (Degrees) (rpm) BS/LA Example 1 137.3 10.0 5477 547.7000 Example 2 137.5 10.1 5492 543.7624 Example 3 137.4 10.0 5409 540.9000 Example 4 137.7 10.1 5337 528.4158 Example 5 137.4 10.2 5302 519.8039 Comparative 137.6 10.8 4267 395.0926 Example 1 Comparative 137.5 10.4 4867 467.9808 Example 2 Comparative 137.7 11.0 4156 377.8182 Example 3 Comparative 137.8 10.8 4502 416.8519 Example 4 Comparative 138.0 10.9 4180 383.4862 Example 5 Comparative 137.9 11.3 4052 358.5841 Example 6 Comparative 138.6 10.8 4345 402.3148 Example 7 Comparative 137.7 10.5 4785 455.7143 Example 8 Calibration 137.3 10.9 4186 384.0367 Ball Comparative 137.9 10.8 4350 402.7778 Example 9

Table 5 shows the results of a BS/LA No. 6 iron test. The No. 6 iron used in this test is a Nike Victory Red Split Cavity No. 6 iron having an X100 (extra stiff) shaft, a 62-degree lie angle, and a 31-degree loft angle. The calibration ball for the BS/LA No. 6 iron test is a USGA/R&A Calibration model golf ball commercially available by Bridgestone Sports. To calibrate the BS/LA No. 6 iron test, the conditions are set to cause the calibration ball to have an initial velocity of 126.4 mph±1 mph, a launch angle of 14.3 degrees±1 degree, and a backspin of 5504 rpm±150 rpm when the calibration ball is hit with the No. 6 iron having a head speed of about 94 mph±1 mph.

The results of the BS/LA No. 6 iron test show that the BS/LA ratio of golf balls prepared according to the present disclosure are substantially different from the BS/LA ratio of the existing golf balls currently available on the market. For example, at 462.3358, Comparative Example 2 has the highest BS/LA ratio of the existing golf balls currently available on the market. At 522.5000, Example 4 has the lowest BS/LA ratio of the golf balls prepared according to the present disclosure. The difference between the BS/LA ratio of Comparative Example 2 and the BS/LA ratio of Example 5 is 60.1642. The BS/LA ratios of the existing golf balls currently available on the market are substantially different from the BS/LA ratios of the golf balls prepared according to the present invention. The BS/LA ratios of the existing golf balls currently available on the market in Table 5 fall within a range of about 364 to about 463. The BS/LA ratios of the golf balls prepared according to the present disclosure in Table 5 fall within a range of about 522 to about 555. In some embodiments, the BS/LA ratios resulting from performing the BS/LA No. 6 iron test on the golf balls prepared according to the present disclosure range from about 500 to about 600. In some embodiments, the BS/LA ratios resulting from performing the BS/LA No. 6 iron test on the golf balls prepared according to the present disclosure range from about 510 to about 580.

TABLE 5 BS/LA No. 6 IRON TEST Initial Launch Velocity Angle Backspin (IV) (LA) (BS) Ball (mph) (Degrees) (rpm) BS/LA Example 1 126.2 13.0 7187 552.8462 Example 2 125.4 12.9 7147 554.0310 Example 3 126.2 12.9 7024 544.4961 Example 4 126.7 13.2 6897 522.5000 Example 5 126.2 13.1 6929 528.9313 Comparative 126.6 14.4 5470 379.8611 Example 1 Comparative 126.2 13.7 6334 462.3358 Example 2 Comparative 126.7 14.5 5358 369.5172 Example 3 Comparative 126.8 14.0 5832 416.5714 Example 4 Comparative 127.2 14.3 5416 378.7413 Example 5 Comparative 127.1 14.5 5285 364.4828 Example 6 Comparative 127.7 14.1 5741 407.1631 Example 7 Comparative 126.4 13.7 6222 454.1606 Example 8 Calibration 126.4 14.3 5504 384.8951 Ball Comparative 127.3 14.1 5816 412.4823 Example 9

Table 6 shows the results of a BS/LA high loft angle test. The high loft angle club used in this test is a Nike Victory Red Split Cavity pitching wedge having a 64-degree lie angle and a 47-degree loft angle. The calibration ball for the BS/LA high loft angle test is a USGA/R&A Calibration model golf ball commercially available by Bridgestone Sports. To calibrate the BS/LA high loft angle test, the conditions are set to cause the calibration ball to have an initial velocity of 96.1 mph±1 mph, a launch angle of 25 degrees±1 degree, and a backspin of 10137 rpm±150 rpm when the calibration ball is hit with the high loft angle club having a head speed of about 71.6 mph±1 mph.

The results of the BS/LA high loft angle test show that the BS/LA ratio of golf balls prepared according to the present disclosure are substantially different from the BS/LA ratio of the existing golf balls currently available on the market. For example, at 414.1600, Comparative Example 2 has the highest BS/LA ratio of the existing golf balls currently available on the market. At 440.4545, Example 5 has the lowest BS/LA ratio of the golf balls prepared according to the present disclosure. The difference between the BS/LA ratio of Comparative Example 2 and the BS/LA ratio of Example 5 is 26.2945. The BS/LA ratios of the existing golf balls currently available on the market are substantially different from the BS/LA ratios of the golf balls prepared according to the present invention. The BS/LA ratios of the existing golf balls currently available on the market in Table 6 fall within a range of about 348 to about 415. The BS/LA ratios of the golf balls prepared according to the present disclosure in Table 6 fall within a range of about 440 to about 461. In some embodiments, the BS/LA ratios resulting from performing the BS/LA high loft angle test on the golf balls prepared according to the present disclosure fall within a range of about 430 to about 480. In some embodiments, the BS/LA ratios resulting from performing the BS/LA high loft angle test on the golf balls prepared according to the present disclosure fall within a range of about 435 to about 465.

In some embodiments, performing the BS/LA high loft angle test with a No. 9 iron or a wedge other than a pitching wedge in place of the pitching wedge may yield the same BS/LA ratio range of about 430 to about 480. For example, performing the BS/LA high loft angle test with a lob wedge, sand wedge, or gap wedge may yield the same BS/LA ratio range of about 440 to about 461. Wedges and No. 9 irons all typically have loft angles of 40 degrees or higher.

TABLE 6 BS/LA HIGH LOFT ANGLE TEST Initial Launch Velocity Angle Backspin (IV) (LA) (BS) Ball (mph) (Degrees) (rpm) BS/LA Example 1 95.1 23.9 10902 456.1506 Example 2 95.3 23.8 10963 460.6303 Example 3 95.1 24.2 10723 443.0992 Example 4 95.4 24.2 10677 441.1983 Example 5 95.4 24.2 10659 440.4545 Comparative 96.0 26.1 9355 358.4291 Example 1 Comparative 95.9 25.0 10354 414.1600 Example 2 Comparative 96.3 26.4 9209 348.8258 Example 3 Comparative 96.3 25.5 9884 387.6078 Example 4 Comparative 96.2 25.8 9584 371.4729 Example 5 Comparative 96.6 26.1 9340 357.8544 Example 6 Comparative 97.3 25.7 9827 382.3735 Example 7 Comparative 95.9 25.0 10315 412.6000 Example 8 Calibration 96.1 25.0 10137 405.4800 Ball Comparative 96.6 25.6 9795 382.6172 Example 9

As used herein, unless otherwise stated, compression, hardness, COR, and flexural modulus are measured as follows:

Compression deformation: The compression deformation herein indicates the deformation amount of the ball under a force; specifically, when the force is increased to become 130 kg from 10 kg, the deformation amount of the ball under the force of 130 kg subtracts the deformation amount of the ball under the force of 10 kg to become the compression deformation value of the ball.

Hardness: Hardness of golf ball layer is measured generally in accordance with ASTM D-2240, but measured on the land area of a curved surface of a molded ball. For material hardness, it is measured in accordance with ASTM D-2240 (on a plaque).

Method of measuring COR: A golf ball for test is fired by an air cannon at an initial velocity of 40 m/sec, and a speed monitoring device is located over a distance of 0.6 to 0.9 meters from the cannon. When striking a steel plate positioned about 1.2 meters away from the air cannon, the golf ball rebounds through the speed-monitoring device. The return velocity divided by the initial velocity is the COR.

As shown in FIG. 3, golf ball 100 may include an inner core layer 110, an outer core layer 120, an inner cover layer 130, and an outer cover layer 140. While the exemplary embodiment of golf ball 100 has been described and illustrated as having four layers, other embodiments may include any number of layers. For example, in some embodiments, golf ball 100 may be a one-piece, two-piece, three-piece, or five-piece ball. In some embodiments, golf ball 100 may include more than five layers. The number of layers may be selected based on a variety of factors. For example, the number of layers may be selected based on the type of materials use to make the golf ball and/or the size of the golf ball.

The type of materials used to make the layers of the golf ball may be selected based on a variety of factors. For example, the type of materials used to make the layers of the golf ball may be selected based on the properties of the material and/or the processes used to form the layers. Exemplary materials are discussed below with respect to the individual layers of the exemplary embodiment. In some embodiments, one or more layers may be made from different materials. In some embodiments, one or more layers may be made from the same materials.

The golf ball may be made by any suitable process. The process of making the golf ball may be selected based on a variety of factors. For example, the process of making the golf ball may be selected based on the type of materials used and/or the number of layers included. Exemplary processes are discussed below with respect to the individual layers of the exemplary embodiment.

In some embodiments, inner core layer 110 may have a diameter ranging from 19 mm to 32 mm. In some embodiments, inner core layer 110 may have a diameter ranging from 20 mm to 30 mm. In some embodiments, inner core layer 110 may have a diameter ranging from 21 mm to 28 mm.

Inner core layer 110 may be made by any suitable process. For example, in some embodiments, inner core layer 110 may be made by an injection molding process. In some embodiments, inner core layer 110 may be made by a compression molding process. The process of making the inner core layer may be selected based on a variety of factors. For example, the process of making the inner core layer may be selected based on the type of material used to make the inner core layer and/or the process used to make the other layers.

In some embodiments, inner core layer 110 may include one or more highly neutralized acid polymer compositions. For example, in the exemplary embodiments, the inner core layer 110 may include two highly neutralized acid polymer compositions. In some embodiments, suitable materials for the inner core layer may include the following highly neutralized acid polymer compositions: HPF resins such as HPF1000, HPF2000, HPF AD1024, HPF AD1027, HPF AD1030, HPF AD1035, HPF AD1040, all produced by E. I. Dupont de Nemours and Company. In some embodiments, the material used to form inner core layer 110 may include a highly neutralized acid polymer composition and optional additives, fillers, and/or melt flow modifiers. The acid polymer may be neutralized to 80% or higher, including up to 100%, with a suitable cation source, such as magnesium, sodium, zinc, or potassium. In the exemplary embodiment, the highly neutralized acid polymer compositions used to make the inner core layer may include the same cation source. Suitable additives and fillers may include, for example, blowing and foaming agents, optical brighteners, coloring agents, fluorescent agents, whitening agents, UV absorbers, light stabilizers, defoaming agents, processing aids, mica, talc, nanofillers, antioxidants, stabilizers, softening agents, fragrance components, plasticizers, impact modifiers, acid copolymer wax, surfactants. Suitable fillers may also include inorganic fillers, such as zinc oxide, titanium dioxide, tin oxide, calcium oxide, magnesium oxide, barium sulfate, zinc sulfate, calcium carbonate, zinc carbonate, barium carbonate, mica, talc, clay, silica, lead silicate. Suitable fillers may also include high specific gravity metal powder fillers, such as tungsten powder and molybdenum powder. Suitable melt flow modifiers may include, for example, fatty acids and salts thereof, polyamides, polyesters, polyacrylates, polyurethanes, polyethers, polyureas, polyhydric alcohols, and combinations thereof.

In some embodiments, outer core layer 120 may be formed by crosslinking a polybutadiene rubber composition as described in U.S. patent application Ser. No. 12/827,360, entitled Golf Balls Including Crosslinked Thermoplastic Polyurethane, filed on Jun. 30, 2010, and applied for by Chien-Hsin Chou et al., the disclosure of which is hereby incorporated by reference in its entirety. When other rubber is used in combination with a polybutadiene, polybutadiene may be included as a principal component. For example, in some embodiments, a proportion of polybutadiene in the entire base rubber may be equal to or greater than 50% by weight. In some embodiments, a proportion of polybutadiene in the entire base rubber may be equal to or greater than 80% by weight. In some embodiments, a polybutadiene having a proportion of cis-1,4 bonds of equal to or greater than 60 mol %, and further, equal to or greater than 80 mol % may be used.

In some embodiments, cis-1,4-polybutadiene may be used as the base rubber and mixed with other ingredients to form outer core layer 120. In some embodiments, the amount of cis-1,4-polybutadiene may be at least 50 parts by weight, based on 100 parts by weight of the rubber compound. Various additives may be added to the base rubber to form a compound. The additives may include a cross-linking agent and a filler. In some embodiments, the cross-linking agent may be zinc diacrylate, magnesium acrylate, zinc methacrylate, or magnesium methacrylate. In some embodiments, zinc diacrylate may provide advantageous resilience properties. The filler may be used to increase the specific gravity of the material. The filler may include zinc oxide, barium sulfate, calcium carbonate, or magnesium carbonate. In some embodiments, zinc oxide may be selected for its advantageous properties. Metal powder, such as tungsten, may alternatively be used as a filler to achieve a desired specific gravity. In some embodiments, the specific gravity of outer core layer 120 may be from about 1.05 g/cm³ to about 1.45 g/cm³. In some embodiments, the specific gravity of outer core layer 120 may be from about 1.05 g/cm³ to about 1.35 g/cm³.

In some embodiments, a polybutadiene synthesized with a rare earth element catalyst may be used to form outer core layer 120. Such a polybutadiene may provide excellent resilience performance of golf ball 100. Examples of rare earth element catalysts include lanthanum series rare earth element compound, organoaluminum compound, and almoxane and halogen containing compounds. Polybutadiene obtained by using lanthanum rare earth-based catalysts usually employs a combination of a lanthanum rare earth (atomic number of 57 to 71) compound, such as a neodymium compound.

In some embodiments, a polybutadiene rubber composition having at least from about 0.5 parts by weight to about 5 parts by weight of a halogenated organosulfur compound may be used to form outer core layer 120. In some embodiments, the polybutadiene rubber composition may include at least from about 1 part by weight to about 4 parts by weight of a halogenated organosulfur compound. The halogenated organosulfur compound may be selected from the group consisting of pentachlorothiophenol; 2-chlorothiophenol; 3-chlorothiophenol; 4-chlorothiophenol; 2,3-chlorothiophenol; 2,4-chlorothiophenol; 3,4-chlorothiophenol; 3,5-chlorothiophenol; 2,3,4-chlorothiophenol; 3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol; 2,3,5,6-tetrachlorothiophenol; pentafluorothiophenol; 2-fluorothiophenol; 3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophenol; 2,4-fluorothiophenol; 3,4-f luorothiophenol; 3,5-f luorothiophenol 2,3,4-fluorothiophenol; 3,4,5-fluorothiophenol; 2,3,4,5-tetrafluorothiophenol; 2,3,5,6-tetrafluorothiophenol; 4-chlorotetrafluorothiophenol; pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol; 4-iodothiophenol; 2,3-iodothiophenol; 2,4-iodothiophenol; 3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophenol; 3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol; 2,3,5,6-tetraiodothiophenol; pentabromothiophenol; 2-bromothiophenol; 3-bromothiophenol 4-bromothiophenol; 2,3-bromothiophenol; 2,4-bromothiophenol; 3,4-bromothiophenol; 3,5-bromothiophenol; 2,3,4-bromothiophenol; 3,4,5-bromothiophenol; 2,3,4,5-tetrabromothiophenol; 2,3,5,6-tetrabromothiophenol; and their zinc salts, the metal salts thereof and mixtures thereof.

Outer core layer 120 may be made by any suitable process. For example, in some embodiments, outer core layer 120 may be made by a compression molding process. The process of making the outer core layer may be selected based on a variety of factors. For example, the process of making the outer core layer may be selected based on the type of material used to make the outer core layer and/or the process used to make the other layers.

In some embodiments, outer core layer 120 may be made through a compression molding process including a vulcanization temperature ranging from 130° C. to 190° C. and a vulcanization time ranging from 5 to 20 minutes. In some embodiments, the vulcanization step may be divided into two stages: (1) the outer core layer material may be placed in an outer core layer-forming mold and subjected to an initial vulcanization so as to produce a pair of semi-vulcanized hemispherical cups and (2) a prefabricated inner core layer may be placed in one of the hemispherical cups and may be covered by the other hemispherical cup and vulcanization may be completed. In some embodiments, the surface of inner core layer 110 placed in the hemispherical cups may be roughened before the placement to increase adhesion between inner core layer 110 and outer core layer 120. In some embodiments, inner core surface may be pre-coated with an adhesive before placing inner core layer 110 in the hemispherical cups to enhance the durability of the golf ball and to enable a high rebound.

In some embodiments, inner core layer 110 may have a high resilience. Such a high resilience may cause golf ball 100 to have increased carry and distance. In some embodiments, inner core layer 110 may have a coefficient of restitution (COR) value ranging from 0.79 to 0.89. In some embodiments, inner core layer 110 may have a COR value ranging from 0.795 to 0.88. The COR value of inner core layer 110 may be greater than the COR value of golf ball 100. In some embodiments, the COR value of inner core layer 110 may be 0.005 to 0.02 greater than the COR value of golf ball 100.

In some embodiments, inner core layer 110 may have a compression deformation value ranging from 2.5 mm to 5 mm. In some embodiments, inner core layer 110 may have a compression deformation value ranging from 3.5 mm to 5 mm. Inner core layer 110 may have a surface Shore D hardness of from 40 to 60. In some embodiments, outer core layer 120 may have a surface Shore D hardness of from 50 to 60, which may be higher than the surface hardness of inner core layer 110.

In some embodiments, inner core layer 110 may have a Shore D cross-sectional hardness ranging from 40 to 60 at any single point on a cross-section obtained by cutting inner core layer 110 in half. In some embodiments, the difference in Shore D cross-sectional hardness at any two points on the same cross-section may be within ±6. In some embodiments, the difference in Shore D cross-sectional hardness at any two points on the same cross-section may be within ±3.

In some embodiments, inner core layer 110 may have a smaller specific gravity than outer layers. Such a difference in specific gravity may cause golf ball 100 to have a greater moment of inertia. In some embodiments, the specific gravity of inner core layer 110 may range from about 0.85 g/cm³ to about 1.1 g/cm³. In some embodiments, the specific gravity of inner core layer 110 may range from about 0.9 g/cm³ to about 1.1 g/cm³.

In some embodiments, inner cover layer 130 of golf ball 100 may have a thickness ranging from 0.5 mm to 1.5 mm. For example, inner cover layer 130 may have a thickness of 1 mm. In some embodiments, inner cover layer 130 may have a thickness ranging from 0.8 mm to 1 mm. For example, in some embodiments, inner cover layer 130 may have a thickness of 0.9 mm.

In some embodiments, outer cover layer 140 of golf ball 100 may have a thickness ranging from 0.5 mm to 2 mm. For example, outer cover layer 140 may have a thickness of 1 mm. In some embodiments, outer cover layer 140 may have a thickness ranging from 1 mm to 1.5 mm. For example, in some embodiments, inner cover layer 130 may have a thickness of 1.2 mm.

In some embodiments, inner cover layer 130 may have a Shore D hardness, as measured on the curved surface, ranging from about 60 to 80. In some embodiments, outer cover layer 140 of golf ball 100 may have a Shore D hardness, as measured on the curved surface, ranging from 40 to 60.

In some embodiments, inner cover layer 130 and/or outer cover layer 140 may be made from a thermoplastic material including at least one of an ionomer resin, a highly neutralized acid polymer composition, a polyamide resin, a polyester resin, and a polyurethane resin. In some embodiments, inner cover layer 130 may include the same type of material as outer cover layer 140. In some embodiments, inner cover layer 130 may include a different type of material from outer cover layer 140.

In some embodiments, golf ball 100 may have a moment of inertia between about 82 g/cm² and about 90 g/cm². Such a moment of inertia may produce a desirable distance and trajectory, particularly when golf ball 100 is struck with a driver or driven against the wind.

In some embodiments, golf ball 100 may include a ball compression deformation of 2.2 mm to 3.2 mm. In some embodiments, golf ball 100 may have compression deformation of 2.5 mm to 3 mm.

In some embodiments, the layers used to make golf ball 100 may have a specified relationship in terms of their respective physical properties. For example, to have greater moment of inertia, the golf ball layers may have a specific gravity gradient increased from inner core layer 110 to outer cover layer 140. In some embodiments, inner core layer 110 may have a first specific gravity, outer core layer 120 may have a second specific gravity greater than the first specific gravity by at least 0.01, and inner cover layer 130 may have a third specific gravity greater than the second specific gravity by at least 0.01.

In some embodiments, golf ball 100 may have 300 to 400 dimples on the outer surface of outer cover layer 140.

While various embodiments of the invention have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims. 

What is claimed is:
 1. A golf ball comprising, an inner core layer; an outer core layer enclosing the inner core layer; an inner cover layer enclosing the outer core layer; an outer cover layer enclosing the inner cover layer; wherein the inner core layer has a higher coefficient of restitution than the outer core layer, the inner cover layer, and the outer cover layer; wherein when the golf ball is hit with a driver having a loft angle of less than 15 degrees, the golf ball has a spin rate to launch angle ratio ranging from about 190 to about 360; and wherein when the golf ball is hit with an iron having a loft angle of less than 40 degrees, the golf ball has a spin rate to launch angle ratio ranging from about 500 to about
 600. 2. The golf ball according to claim 1, wherein performing the BS/LA 160 mph driver test on the golf ball results in the golf ball having a spin rate to launch angle ratio ranging from about 190 to about
 230. 3. The golf ball according to claim 1, wherein performing the BS/LA No. 4 iron test on the golf ball results in the golf ball having a spin rate to launch angle ratio ranging from about 510 to about
 580. 4. The golf ball according to claim 1, wherein performing the BS/LA No. 6 iron test on the golf ball results in the golf ball having a spin rate to launch angle ratio ranging from about 510 to about
 580. 5. The golf ball according to claim 1, wherein performing the BS/LA high loft angle test on the golf ball results in the golf ball having a spin rate to launch angle ratio ranges from about 440 to about
 480. 6. The golf ball according to claim 1, wherein the inner core layer includes at least one highly neutralized acid polymer composition.
 7. The golf ball according to claim 1, wherein the inner core layer has a coefficient of restitution value ranging from about 0.795 to about 0.88.
 8. The golf ball according to claim 1, wherein the inner core layer has a coefficient of restitution value that is about 0.005 to about 0.02 greater than the coefficient of restitution value of the golf ball.
 9. The golf ball according to claim 1, wherein the inner cover layer has a Shore D hardness ranging from about 60 to about
 80. 10. A golf ball comprising, an inner core layer; an outer core layer enclosing the inner core layer; an inner cover layer enclosing the outer core layer; an outer cover layer enclosing the inner cover layer; wherein the inner cover layer has a greater specific gravity than the thermoset outer core layer; wherein when the golf ball is hit with an iron having a loft angle of less than 40 degrees, the golf ball has a first spin rate to launch angle ratio; and wherein when the golf ball is hit when with a driver having a loft angle of less than 15 degrees, the golf ball has a second spin rate to launch angle ratio, wherein the second spin rate to launch angle ratio is at least 240 lower than the first spin rate to launch angle ratio.
 11. The golf ball according to claim 10, wherein the golf ball has a second spin rate to launch angle ratio that is at least 310 lower than the first spin rate to launch angle ratio.
 12. The golf ball according to claim 10, wherein the inner cover layer and outer cover layer both comprise thermoplastic materials.
 13. The golf ball according to claim 10, wherein the outer core layer includes a polybutadiene rubber.
 14. The golf ball according to claim 13, wherein the thickness of the outer core layer ranges from about 0.5 to about 2 mm.
 15. The golf ball according to claim 10, wherein the inner core layer has a coefficient of restitution value that is about 0.005 to about 0.02 greater than the coefficient of restitution value of the golf ball.
 16. The golf ball according to claim 10, wherein the inner cover layer has a Shore D hardness ranging from about 60 to about
 80. 17. A golf ball comprising, an inner core layer; an outer core layer enclosing the inner core layer; an inner cover layer enclosing the outer core layer; an outer cover layer enclosing the inner cover layer; wherein the inner core layer has a higher coefficient of restitution than the outer core layer, the inner cover layer, and the outer cover layer; wherein when the golf ball is hit with a driver having a loft angle of less than 15 degrees, the golf ball has a spin rate ranging from about 2400 rpm to about 2800 rpm; and wherein when the golf ball is hit with a first iron having a loft angle of less than 40 degrees, the golf ball has a spin rate ranging from about 6800 rpm to about 7300 rpm.
 18. The golf ball according to claim 17, wherein the first iron having a loft angle of less than 40 degrees is a No. 6 iron.
 19. The golf ball according to claim 17, wherein when the golf ball is hit with the first iron having a loft angle of less than 40 degrees, the golf ball has a launch angle ranging from about 12 degrees to about 13.5 degrees.
 20. The golf ball according to claim 17, wherein when the golf ball is hit with a second iron having a loft angle of less than 40 degrees, the golf ball has a spin rate ranging from about 5300 rpm to about 5600 rpm.
 21. The golf ball according to claim 20, wherein when the golf ball is hit with the second iron having a loft angle of less than 40 degrees, the golf ball has a launch angle ranging from about 9.5 degrees to about 10.5 degrees.
 22. The golf ball according to claim 20, wherein the second iron having a loft angle of less than 40 degrees is a No. 4 iron.
 23. The golf ball according to claim 17, wherein when the golf ball is hit with a second iron having a loft angle of 40 degrees or greater, the golf ball has a spin rate ranging from about 10,500 rpm to about 11,100 rpm.
 24. The golf ball according to claim 23, wherein when the golf ball is hit with a second iron having a loft angle of 40 degrees or greater, the golf ball has a launch angle ranging from about 21 degrees to 23 about degrees. 